Considering the obvious benefits of fusion energy and the considerable
efforts spent trying to attain them, why hasn't fusion research so far
produced better results?

"Actually, fusion research has made remarkable progress in recent years. There
is no longer any question of its scientific feasibility: near breakeven (the
state at which the fusion power produced equals the power consumed to
sustain the plasma) has been demonstrated with actual fusion fuels in
Princeton's nearly 20-year-old Tokamak
Fusion Test Reactor (TFTR). Dramatically improved operating regimes have
recently been discovered that may form the basis of a practical energy
reactor. An alternate approach, known as inertial confinement fusion, has
also made substantial progress. Inertial confinement fusion is poised to
demonstrate better than break-even gains at the turn of the century. The
clear key to this progress has been advances in understanding the scientific
underpinnings of plasmas and of fusion science. In the process, several
billion-dollar-per-year applications of plasmas have emerged.

"The questions at hand now are really: Will fusion energy become practical
and economically feasible? Is society willing to make the necessary investment
to find out if the answer is yes?

"When fusion research began in earnest 30 years ago, people simply did not
appreciate the complexity and subtlety of the science of plasmas, and the
concomitant depth of understanding that would be needed to make controlled
fusion work. Scientists also vastly underestimated the engineering
requirements and constraints--a result both of naivete and unknown scientific
hurdles. And it is natural that the closer one gets to the goal of practical
energy, the longer each next step takes. The experimental devices grow
larger and more expensive as one approaches a commercially viable fusion
reactor.

"Is it worth continuing fusion development? If scientists conclude that the
burning of fossil fuels is inducing unacceptable global climate change, then
we have a limited number of alternatives to turn to: solar-based sources
(photovoltaics, ocean, wind, etc.), nuclear fission and fusion. Solar-based
sources will be increasingly important in niches but can not supply
humanity's bulk power demands, particularly if worldwide standards of living
continue to rise. Nuclear fission could fill the gap, but it has well-known
disadvantages.

"So the question really becomes: Can we afford to take the risk not to
vigorously pursue fusion? One new power plant costs between $1 billion and
$10 billion these days; a new generation of power plants would total about
$10 trillion! Is fusion research funding of around a billion dollars per
year for even 50 more years a reasonable gamble? It is to me."

Charles C. Baker, associate director for fusion at the School of Engineering at the University
of California, San Diego, and the International Thermonuclear Experimental
Reactor (ITER) U.S. Home Team Leader, adds his views:

"Thank you for giving me the opportunity to respond to this question. First,
let me state that I disagree with the premise of the question. Research in
magnetic-confinement fusion has produced excellent results. In the past 15
years, research in the U.S. and other countries has increased by 10,000,000
times the fusion power level produced in experiments, and we have now
achieved production of 10 megawatts of fusion power on the Tokamak Fusion
Test Reactor at Princeton. (A tokamak
is a kind of magnetic donut that has proven to be a particularly stable way
to confine the extremely hot plasma needed to achieve fusion.) This dramatic
progress has been accomplished through investments made by the U.S., Europe,
and Japan during the 1970s on a new, more powerful class of tokamak
experiment.

"The next step in power reactor performance levels, at which the plasma is
capable of ignition and plasma 'burn' (wherein most of the heating energy
comes from the fusion reactions), again requires a new, more powerful
experimental device. The U.S. tried to proceed with a next-step burning
plasma experiment in the 1980s, but was unable to obtain congressional
funding. The U.S., Europe, Japan and Russia are now collaborating on the
design and R&D work for a project called the International Thermonuclear Experimental
Reactor. ITER is designed to achieve plasma ignition and long-pulse
burn. It will also demonstrate the technology required for the core of a
fusion power plant and the systems needed for extracting power from the
device. This six-year collaboration, called the Engineering Design
Activities, began in 1992, and exploratory discussions are now underway
concerning cost-shared, international construction of this device. Such an
engineering test reactor is required by all parties for progress toward
practical fusion energy, so cost sharing for this step is mutually
advantageous.

"The combined results from a variety of tokamaks around the world have
produced an impressive set of achievements. Neutral beams and a variety of
radio-frequency heating methods can provide tens of megawatts of heating
power for creating high-temperature plasmas. Experimental devices have
produced ion temperatures as high as 45,000 electron volts and densities of
approximately 1020 particles per cubic meter, sufficient for fusion
reactors. An important overall measure of physics performance is the 'triple
product' of the peak ion density, the plasma energy confinement time and the
peak ion temperature. A triple-product value of 7 x 1024 electron
volt-seconds per cubic meter is required for an ignited, deuterium-tritium
reactor. JT-60U,
a large Japanese tokamak, has already achieved triple products of 1.3 x
1024 electron volt-seconds per cubic meter.

"The nominal fusion power of ITER is 1,500 megawatts; it represents a
framework for a full-size fusion power reactor, though it is not designed to
produce electricity. An extrapolation of the present knowledge of tokamaks
indicates that commercial fusion reactors will be rather large and
expensive. Fortunately, ongoing research programs are revealing ways to
improve substantially the performance of tokamak reactors. These promising
new directions include higher fusion power densities, and hence smaller
reactors; development of 'transport barriers' in the plasma, leading to
improved energy confinement and smaller sizes; self-driven plasma currents
that permit steady-state operation and low recirculating power; and the
development of advanced divertor concepts to provide particle control and
heat removal over long reactor lifetimes.

"The rate of progress in the fusion program is consistent with the level of
resources being devoted to it. Actual funding has been much less than
anticipated during the detailed planning drawn up in the 1970s and 1980s.
Present levels of funding in the U.S. ($244 million in fiscal year 1996) are
not sufficient to keep pace with the earlier plans. As a result, the U.S. is
unfortunately passing its traditional leadership in magnetic fusion to
Europe and Japan.

"In August 1996, the U.S. Department of Energy issued a Strategic Plan for
the Restructured U.S. Fusion Energy Sciences Program. The nation's previous
strategy was a schedule-driven development program to prove fusion to be a
technically and economically credible energy source, with the goal of an
operating, demonstration power plant by about 2025. In a climate of severe
budgetary constraints, however, that strategy became highly unrealistic. In
an attempt to stay as close as possible to the goal-oriented schedule, the
fusion program has concentrated almost all of its available resources on the
tokamak concept, virtually eliminating support for alternative approaches
and for basic plasma science. Despite impressive scientific progress, the
program continues to receive insufficient resources.

"The new strategy emphasizes an international effort aimed at advancing the
scientific knowledge base needed for the development of an economically and
environmentally attractive fusion energy source. To be a credible partner in
this long-term quest, the U.S. needs a vigorous domestic program in fusion
science and technology. At a constant level of funding, the restructured
U.S. program will be able to focus on fusion's underlying scientific
foundations and will enable the nation to take the lead in selected areas of
expertise as part of the international effort to develop fusion energy.

"The restructured U.S. program will strive to remain a credible partner in
the international fusion program that includes both ITER and many smaller
projects in all areas of fusion science and technology. Given the high
projected cost of creating a burning physics experiment and given that the
U.S. now funds only about one sixth of the world research effort, a strategy
based on international collaboration on fusion energy research and
development can be highly cost effective.